Power transmission



Oct. 15, 1957 E. F. KLESSIIG ET AL 2,809,593

POWER TRANSMISSION Filed July 21, 1953 2 Sheets-Sheet l FIG. 5

INVENTORS ERNST F. KLESSlG GLENN M. JONES ATTORNEY Oct. 15, 1957 E. F. KLESSIG ErAL 2,809,593

' POWER TRANSMISSION Filed July 21, 1953 2 Sheets-Sheet 2 mmvrons ERNST F. KLESSIG Y GLENN M. JONES ATTORNEY El L fit

PQWER TRANSMISSION Application 31113; 21, 1953, Serial No. 39,315

9 Ciairns. (Cl. 103-136) This invention relates to power transmissions, and is particularly applicable to those of the type comprising two or more fluid pressure energy translating devices, one of which may function as a pump and another as a fluid motor.

More particularly the present invention relates to a rotary device of the sliding vane type capable of function as either a pump or a motor.

In such devices the vanes are normally mounted in a rotary part of the mechanism and are thrown out into abutment with a relatively stationary member by centrifugal force. In the absence of preventative provisions, operating pressure of the unit exerted over a portion of the outer ends of the vanes would exert a force far in excess of centrifugal force on the vanes and cause them to retract into the rotary member. The most widely used and successful methods for preventing vane retraction have utilized fluid pressure applied to the underside of the vanes to counterbalance pressure forces on the outer end. These prior schemes may be divided broadly into two classes, namely those in which continuous high pressure is maintained on the underside of the vanes regardless of the varying force required to maintain the vane outward as it passes through an operational cycle, and those systems wherein the high pressure is applied only intermittently, in phase with the application of high pressure to the outer end of the vanes, and a lower pressure is applied when the outer end of the Vane is exposed to low pressure.

In the intennittent pressure system, alternate high and low pressure ports are provided to supply fluid to the underside of the vanes. These ports are so positioned with reference to the main ports of the unit as to efiect transition of the pressure on the underside of the vane from low to high in phase with the change of pressure exerted on the outer end from low to high, and vice versa. In such a scheme the timing of application of pressure to the underside of the vane with reference to the application of pressure to the outer end is extremely important. if pressure is directed to the underside of the vane too late, the vane will momentarily retract which is highly undesirable. If pressure is applied to the underside of the vanes too soon, excessive wear results at the point of application and the life of the unit is greatly shortened. Unavoidable machining irregularities make it almost impossible to prevent one or the other of these disadvantages in an intermittent pressure system.

The other scheme which has been widely used is to apply a continuous high pressure to the underside of the vane regardless of fluctuation in pressure on the outer end during the operating cycle. The disadvantage of such a scheme is that during those portions of the cycle when only low pressure is exerted on the outer end of the vanes, the vanes are urged outward by an unnecessarily large force which causes excessive wear and results in a lowered mechanical efficiency.

It is an object of this invention to provide an improved vane type rotary fluid pressure energy translating device.

rates atet More particularly it is an object of this invention to provide such a device in which the vanes are maintained outward by a positive pressure applied to the underside of the vanes, which pressure application is instantaneous with increase in pressure on the outer end of the vanes.

Another object is to provide such a device which is capable of low cost construction and long service life.

Another object is to provide such a device which is easily adaptable for reversed rotation, and which may be operated as either a pump or a motor.

Further objects and advantages of the present invention Jill be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of the present invention is clearly shown.

In the drawings:

Figure 1 is a longitudinal section through a vane type fluid pressure energy translating device embodying the present invention.

Figure 2 is a section taken on line 2-2. of Figure 1.

Figure 3 is a section taken on line 33 of Figure 1.

Figure 4 is a section taken on line 44 of Figure 1.

Figure 5 is a partial section taken on line 55 of Figure 2.

Figures 6 through 11 are representations of the working parts of the pump shown in various positions during an operating cycle and illustrating the positional relation of the ports and those parts.

Figure 12 is an enlarged fragmentary view of the tip of one of the vanes of the unit contacting the cam contour.

Referring now to Figure 1 there is shown a pressure energy translating device of the radially sliding vane type capable of functioning as either a pump or a motor. The device includes a body member 10, a ring member 12, and a head member 14 secured together in a sandwich relation by a plurality of bolts 16 to form a housing 17. Bolts 16 extend through the head 14 and the ring 12 into threaded holes in the body 19. A pair of O-ring seals 18 and 20 are provided to prevent leakage at the juncture of the housing parts. Ring 12 has machined therein a generally elliptical cam contour 22. A rotor 24 of substantially the same axial thickness as the ring 12 is located in the cavity formed by the cam contour 22 and is spline connected to, and supported by, a drive shaft 26 which is in turn supported in the body member 10 by a pair of ball bearings 28 and 39. A conventional shaft seal 32 prevents leakage from the housing 17 at the point of egress therefrom of the shaft 26.

The rotor 24 is provided with a plurality of substantially radial slots 34 in each of which is slidably positioned a vane 36. Vanes 36 are of substantially the same axial width as are the ring 12 and the rotor 24. The body member 10 presents a smooth, plain face 33 against which the ring 12, rotor 24, and vanes 36 axially abut. The opposed end faces of the ring, rotor, and vanes are abutted by the plane face 44 of a pressure plate 42 which is positioned in a cavity 44 in the head member 14, and forms therewith a pressure chamber 46. A spring 5-3 maintains the pressure plate 42 in endwise abutment with the ring, rotor, and vanes, and fluid pressure in the chamber 46 induces deflection of the pressure plate 42 in such a manner as to cause reduced end clearance with increased operating pressure. Pumping mechanism of this general type is described in more particularity in the patent to Gardiner et al., 2,554,988.

Dowels 4-7 extend from the body member it) through the ring 12 and into the pressure plate 2 to maintain the desired angular relation therebetween. it should be noted that the dowels are symmetrically arranged to permit reversing the ring for reversed rotation as hereinafter described.

As can best be seen in Figure 3 the space radially included between the rotor 24 and the cam contour 22 in working spaces 50 and 52'. The vanes 36 extend radial- 1y across the working spaces to abut the cam contour and to forth between eachpair. of, adjacent vanes a working chamber. It canbfe seen that during rotation of the rotor 24 .the working. chambers between the vanes will alternately expand and contract as they move through the working spaces 50 and 52. A pair of kidney-shaped low pressure ports54 and 56 are so positioned in the face 38 of body 14 as to overlie the working spaces 59 and 52 in the zone wherein the working spaces areincreasing in size when the device is, operated. as a pump, and conversely, where they are decreasing in size the device is operated as a moton. A low pressure, external connection port 58 is provided in the body member 14), which communicates with low pressure ports 54 and 56.

In. a similar manner ajpair of high pressure kidneyshaped ports 60 and 62 are provided in the plane face 40 of the pressure. plate 42,. Ihese'kidney ports overlie the working spaces 50 and 52 in the zone wherein the worka ing chambers are decreasing in size during operation as a pump, or are increasing in size when the device is operating as a motor. git shouldbe noted that these high pressure portsfitl and 62 .extenddirectly through the pressure plate 42 tofcommunicate with the pressure chamber 46; Thus, operating pressure of the unit exists in the chamber 46 at all times. A passage 64 in the head 14 extends from the'pressure chamber 46 to an external high pressureconnection port 66.

During operation as a pump, the rotor 24 is driven by the shaft 26in a clockwise direction as the device is viewed fromthe shaft end. Fluid is drawn into the expanding working chambers as they pass the low pressure ports 54 and 56, and is expelled therefrom as they contract in passing the high pressure ports 60 and 62. Thus during operation as a pump the external connection port 58 becomes an inlet port and the external connection port.

66 becomes an outlet port. When the device is operated .asa motor, a source of fluid pressure is connected to the port 66 and the fluid passes into the pressure chamber 46 and through thehigh'pressure ports 60 and 62 to drive the rotor and hence. the shaft 26 in a counterclockwise direction when the device is used from the shaf end. The fluid'isexhausted through low pressure 'portS 542136 55 tothe external connection port 58.

Duii'ng operation it is necessary that the vanes 36 be maintainedfirmly against the cam contour 22 to prevent fluid slip and fpoorvolumetric efiiciency. This problem is complicated by the. fact that 'theends of the vanes 36 are normally rounded, thus. exposing a substantial area {atthe outer, end of the ,v'anesfto the pressure aheadof and behind the vane. Ihis condition can best'be seen by reference to the enlarged view, shown by Figure 12,

.of a vane 36 contacting the cam contour 22; Assuming that high pressure exists on the side 68 andthe low pressure exists on the side 79, forces exerted on the outer end 72'of the vanefits are as indicated by the arrows 74 and 76. To counteract the forces indicated by the arrows 74 and 76, which tend to force the vane away from the cam contour and thus cause iretrac'tion or collapse of the vanes 36, various 'schemeshave been used in the past, noneof which has been completely successful for reasons hereinafter noted. j,

One scheme which has metiwith wide acceptance due to itssimplicity and 'efiectiveness is illustrated in the heretofore mentioned patent to Gardiner et al. In the device there illustrated the .operating pressure of the unit' is applied at all times to the underside of the-vanes, thus 1 finaintaining them outward and preventing their retraction due to pressure on the outer'end. One disadvantage to this scheme is that when the outer ends of the vanes :are exposed to low pressure, the outward biasing forc e due to pressure under the vanes continues atan unneces V sarily high level resultingin wear and reduced'mechanical .eihciency.

Another attempted solution of the problem is illustrated in the patent to Kendrick, No.- 2,255,784. Kendricks device utilizes spaced ports which conduct fluid pressure to the underside of the vanes and those ports are so located and connected that the pressure on the underside of the vane substantially equals the greatest pressure on the outer end of the vanes at the various positions it occupies during operation. One of the disadvantages of the lastnamed scheme is that, due to unavoidable machining irregularities, high pressure may be directed to the underside of the vane an instant before it is imposed on the outer end, or perhaps be imposed on outer end an instant before it is directed to the underside of the vanes. In the event of prior application of pressure to the underside of the vane, a sharply defined point of wear will appear on the cam ring. In the event'of too late an application of pressure tothe underside of the vane pressure on the outer end will induce vane retraction which is aneven less desirable condition.

The preserit invention provides means for hydraulically biasing the vanes into contact with the ring and avoids the difiiculties inherent in prior schemes. As hereinafter described, the present invention insures the simultaneous application of pressure to both the outer and the inner ends of the James, thus preventing retraction and avoiding unnecessary wear. V

In the embodiment herein illustrated there are provided a pair of. auxiliary low. pressure ports 78 and 89 inthe face 33 of the body member 10. These ports are so positioned as to communicate with the enlarged inner ends 82 of the. vane slots 34 during rotation of the rotor 24.

A pair of drilled balancing passages 84 and 86 extend.

frorn'the low pressure ports 54 and55 to respectively connect them to the auxiliary low pressure balancing ports '78 and 80. Thus, during the time the enlarged inner ends 820i the vane slots 34 are in communication with either of the auxiliary low pressure ports 8i? the pressure on the efiective area 88 at the inner end of the vane in that slot will be the same as that in the low pressure ports "54 and 56. e

In a similar manner there is provided in the face 40 of the pressure plate 42 a pair of auxiliary, kidneysh aped high pressure balancing ports 96 and 92; High pressure fluid is conducted toth'e auxiliary ports 90 and 92 through a pair of drilled balancing passages 94 and 96 which extend directly through the pressure plate 42 to communicate with the pressurechamber 46. As heretofore discussed, operatingpressure of chamber pressure in auxiliary high pressure ports 96 and will thus be the same as that in the high into the sameplane they are, as will be understood from the conformation of the ports, angularly spaced from i one another as can be seen by reference to Figure 6. 'Durrngrotanon of the rotor 24', as the enlarged inner ends of the vane slots 3'4 pass throughthose zones'wh'erein the auxiliary ports are Jangularly spaced apart, they are isolated. from both the auxiliary low pressure ports and the auxiliary-high pressure ports. In these zones this invention provides supplemental balance porting formed by drilled passages 98, 190, I02, and 104 extending into thepressure plate 42. .Aplurality of drilled passages 106 in 'thejp'ressure plate .2 connect the supplemental ports 9.8, rill i02,and'1li4, respectively, to drilled passages 168, Ht 112, and 114 which extend from the face 400i 7 the pressure plate 42 to intersect the drilled passages 10 6. Passages 108, 110, 112, and1 1 4 are so positioned in the pressure plate 42 as to communicate; with the working spaces 50 and-52 atpoints in-proximity to the endsofthe highpressure ports 60 and 62.

the unit exists in The diameter of passages 1G8, 110, 112, and 114 is selected to be less than the thickness of vanes 36 so as to prevent the bypass of fluid from one side of the vanes to the other as they cross over those passages.

Operation of the invention can best be understood by reference to Figures 6 through 11 where the rotor 24 is illustrated in different positions occupied during operation of the device. Ports 54 and 62, auxiliary ports 78 and 92, supplemental port 106, and passage 119 are schematically indicated in dotted outlines in Figures 6 through 11. The ports are illustrated as being axially projected into a single plane, and are in their true angular positional relation with respect to the cam ring 22. it can be seen in Figures 6 to 9 that the ports 54 and 62 have greater angular spacing than the angular extent of the various working chambers. The region between ports and 52 may be termed a transition zone since the working chambers passing therethrough are isolated from both the ports 54 and 62, and undergo a transition from low to high pressure. This is called closed center valving. Passage 34, which connects between ports 92 and port 62, is also illustrated in dotted lines as is the drilled passage 1% connecting between port 169 and passage 110, and the drilled passage 96 which is shown cting port 92- to port 62.

Assuming the rotor 24 is turning in the direction indicated by the solid arrow 11S and that the device is operating as a pump, the working chamber 120 between the vanes E23 and will be in communication with the low pressure port The enlarged inner end 82 of the vane slot 3% which contains vane 122 conducts low pressure to the area 123 at the inner end of the vane, by reason or" being communication with the auxiliary low pessure port 78.

As the rotor turns the direction indicated by the arw 8, from the position illustrated in Figure 6 to that igure 7, it can be seen that vane 122 has port 54 and that direct communication chamber and the low pressure port ed. However, in this position the of the vane slot containing vane 122 between auxilia y low pressure port t Thus the low presi be conducted from port 78 to port rged inner end of the vane slot and conthrough the passage 1535 to the ing 0" amber 126. it can be seen that this Jill continue in Working chamber 121 until r end of the vane slot associated with vane 122 ...oves out of communication with the auxiliary low pressure port "8. When this happens the pressure in working chamber 2% assume some pressure intermediate between the and low pressure dependent on the leakage r of the chamber.

1 ure 8 illustrates the rotor 24 as having moved to a ion such that the vane slot of vane 122 is out of position, pressure in working chamber 129 be intcrlr ate between the high and low pressures. i urrher, that intermediate pressure will be conducted through passages and 1% and port 1 99 to the inner ad the vane slot thus exert an outward biasing orce on the vane 122. Such an arrangement insures tl1"-t the pressure on the outer end of the vanes will not "he sudden occurrence of no ten ency to retract the vane 122 since that same high 6 pressure is instantaneously conducted from the chamber 124 to the underside of the vane 122 by the passages 11?, 106, and port 100. It should be noted that by this scheme pressure is applied to the underside of the vanes to prevent retraction thereof at the instant it is required and not before, thus avoiding excessive wear.

the rotor 24- moves from the position illustrated in Figure 9 to that illustrated in Figure 10 the enlarged inner end of the vane slot associated with vane 122 spans the gap between port 1% and the high pressure port 92 insure high pressure is maintained on the underside the vane 122 at all times that high pressure exists on the outer end.

As illustrated in Figure 11, the rotor 24 has moved to a position such that the enlarged end of the vane slot associated with vane 122 is in communication only with the auxiliary high pressure port 92, and the vane 130 which trails vane 122 has moved to approximately the position vane 122 occupies in Figure 6. The subsequent pressure conditions relating to Working chamber 132 and vane 131? will be as heretofore described for working chamber 126 in vane 122. The same cycle is repeated for all the vanes and the working chambers included therebetween during operation of the device.

As can be seen by reference to Figures 2 and 4 the porting in the device illustrated is symmetrical about an axis 134 extending through the centers of the low pressure ports 54 and S6 and also about an axis 136 extending through the centers of the high pressure ports 60 and 62. It should also be noted that the major axis 138 of the elliptical earn contour 22 is disposed at an angle of 45 to the axes 13 i and 135. Such an arrangement permits adaptation of the device for operation in a reverse direction of rotation by merely removing bolts 16 and flopping the ring 12 180 about either the axis 134 or the axis 136. The reassembly of the remainder of the parts in the positions illustrated effects conversion for upposite rotation. In Figures 6 through 11 the dot-dash outline 140 indicates the position the cam contour 22 will occupy after reversal of the ring 12. Starting with Figure 11 and assuming rotation of the rotor 24 to be opposite that indicated by the arrow 118, and further assuming that the vanes abut the cam contour indicated by the dotdash outline 148, it can be seen that the working chamber 142 included between the vanes 122 and 124 will be exposed to the high pressure port 62, and that the underside of vane 122 will have pressure conducted thereto through the auxiliary high pressure port 92.

As the rotor moves to the position illustrated in Figure 10, the enlarged inner end or" the vane slot associated with vane 122 will bridge the gap between port 92 and port 100, thus continuing the supply of high pressure fluid to the underside of vane 122 while the working chamber 142 remains in communication with the high pressure port 62. As the rotor 24 moves into the position shown in Figure 9, fluid conducted to port through passages and 1136 becomes the sole source of high pressure fluid supply to the underside of the vane 122. The full high pressure of port 62 will be maintained on the underside of vane 122 until, as the rotor 24 moves from the position shown in Figure 9 to that shown in Figure 8, the leading edge of vane 124 passes the end of port 62 and blocks communication between the working chamber 142 and the high pressure port 62. In the position shown in Figure 8 the outer end of vane 122 will be exposed on one side to pressure in the low pressure port 54, and on the side adjacent working chamber 142 to some intermediate pressure dependent on leakage to and from the working chamber 142. It can be seen, however, that this intermediate pressure will be conducted to the underside of vane 122, thus maintaining it in contact with the ring. As the rotor 24 moves from the position shown in Figure 8 to that of Figure 7, the enlarged inner end of the vane slot associated with the vane 122 bridges the gap between the port 100 and the auxiliary pressure a port 76, thus simultaneously dropping the pressure in working chamber 142and on the inner end of the vane 122 to the low value existing in port 78. As the rotor moves to the position shown in Figure 6 the enlarged portion of theslot carrying vane 122 moves out of communication with port 100 and into sole communication with the port 78 to thus maintain the desired lowpressure on the underside of vane 122 while the outer end is exposed only to the low pressure existing in port 54.

The device is capable of operation as a fluid motor and the direction of operation maybe reversed in the same'manner as when operating as a pump. Referring first to Figure 11 and assuming that a supply of high pressure fluid. is connected to the high pressure port 62, the rotor 24 will be driven in a direction of rotation which-is opposite to the arrow 118. Pressure in the working chamber 120 between the vanes 122 and 124 .Will of course be .the high pressure existing in port 62.

The pressure on the underside of the vane 122 will be 'the same high pressure and is conducted to the vane slot associated with vane 122 by the auxiliary high pressure port 92; As the rotor 24 turns from the position illustrated in Figure ll to that illustrated inFigure 10, the

enlarged innerend of the vane slot associated with vane 122 will bridge the gap between the auxiliary high pressure port 92 and the port 10%, and the pressure on the underside otvane 122 will be maintained at the same high pressure existing at port 62 andin Working chamber 120. As the rotor is driven from the position shown in Figure 10 to'that shown in Figure 9 the vane slot associated with vane 122 moves out of communication with port 92, but high pressure is conducted from the working chamber 120 to the underside of the vane 122 by the passages 110 and 106 and the port 100, thus maintaining the vane outward. As the rotor moves to the position shown in Figure 8 the'leading edge of vane 124 will isolate working chamber 120 from communication with thehigh pressureport' 62, resulting in the development ofsomeintermediate pressure in the working chamber 120.{This'intermediate'pressure will of course be conducted to the underside of vane 122 by passages 110, 106, and port 100. As the rotor 24 turns to the position shown in Figure 7, the enlarged inner end of the slot associated with. the 'vane 122 communicates with the "auxiliary low pressure port 78, thus instantaneously dropping the pressure inthe working chamber 120 and under the vane 122 to the low pressure existing in port 78. In 1 moving from the position shown in Figure 7 to that shown in Figure -6'-the enlarged inner end of the vane slot moves into exclusiv e communication with the auxiliary low pressure port 78 thnsmaintaining the pressure a on theunderside of vane 122 at the desired low level while 'the' outer end is in communication with the low. pressure port 54.

It can be seen that there has been provided by'this invention asimple, lowcost, vane type fluid pressure energy translating device which incorporates an improved arrangement'for applying fluid pressure to'maintain the vanes outward against forces tending to-retract the vanes produced by pressure on the outer ends. Further, the

' invention has provided-a schemetfor pressure biasing'of the vanes which affords improved operation, longer life, andihigher efliciency by reason of precise timing in the application of fluid pressure tothe outer and inner ends of the vanes. a

, It is also important to note-that the device is capable of efficient function as either a pump or 'a motor, and

is easily adaptableto 'either direction of rotation.

Whilethe form of embodiment of the invention as herein disclosed'eonstitutes a preferred form, it is to be understood ;that otherjforms might be adopted, all coming within ;the;scope iof the claims which follow.

-What is'claimed ises follows: lJA rotary fluid pressure energy translating device comprisingr a :pair of relatively rotatable members hav- 1 ing included therebetween a working space; a plurality of vanes slidable in one of said members to extend across the working space and abut the other of said members, said vanes and members cooperating to form alternately contracting and expanding working chambers; means forming high andlow pressure valve ports to provide fluid communication with said working chambers, in proper phase with the expansion and contraction thereof; and means for biasing said vanes into abutment with said other member, including means forming an'eflective area associated with each of said vanes to exert force thereon when exposed to fluid pressure, passage forming means in said one member forming passages leading to each of said effective areas, means forming a balancing passage extending from each of said high and low pressure ports to alternately effect communication, through said passage forming means, with the effective areas associated with said vanes, and means forming a supplemental balancing passage, fixed relative to said other member, extending from said working space to successively connect, through said passage forming means, the effective area associated with each vane with said working space at a point between the high pressure port and that vane while said areas are isolated from the other balancing passages, whereby fluid pressure induced vane retraction is prevented and excessive wear is avoided. 2. A rotary fluid pressure energy translating device comprising: a pair of relatively rotatable members having included therebetween. a working space; a plurality of vanes slidable in one of said members to extend across the working space and abut the other of said members, said vanes and members cooperating to'form alternately contracting and expanding working chambers; means forming high and low pressure valve ports to provide fluid communication with said working chambers, in proper phase with the expansion and'contractio'n thereof; and,

means for biasing said vanes into abutment with said other member, including means forming an efiective area' associated with each of said vanes to exert force thereon when exposed to fluid pressure, first passage forming means in said one member forming passages leading to each of said effective areas, second passage forming means forming a balancing passage extending from each of said high and low pressure ports to alternately efiect communication, through said first passage forming means, with the effective areas associated with said vanes, and third passage forming means forming a supplemental balancing passage, fixed relative to said other member, extending from said working space to successively connect, through said first passage forming means, the eifective area associated with each vane with said working space at a point between the high pressure port and that vane while'said areas are isolated from the other balancing passages, said first, second, and third passage forming means being so proportioned and positioned that during. operation said first passage forming means intermittently establish communication between said second and third passage form ing means, whereby fiuid pressure induced vane retraction is prevented and excessive wear is avoided.

3. A .rotary fluid pressure energy translating device abutment with the outermember, including means;formingan efiective area associated with each of said. vanes. "to exert force thereon when exposed to fluid pressure,pas-

sage forming means in the inner member forming passages leading to each of said efiective areas, means forming a balancing passage extending from each of said high and low pressure ports to alternately elfect communication, through said passage forming means, with the effective areas associated with said vanes, and means forming a supplemental balancing passage, fixed relative to said outer member, extending from said working space to successively connect through said passage forming means, the eflective area associated with each vane with said working space at a point between the high pressure port and that vane while said areas are isolated from the other balancing passages, whereby fluid pressure induced vane retraction is prevented and excessive wear is avoided.

4. A rotary fluid pressure energy translating device comprising: a pair of relatively rotatable telescoped members having included therebetween a generally crescentshaped working space; a plurality of vanes slidable in the inner of said members to extend across the working space and abut the outer of said members, said vanes and members cooperating to form alternately contracting and expanding working chambers; means forming high and low pressure valve ports adjacent opposite ends of said working space to provide fluid communication with said working chambers, in proper phase with the expansion and contraction thereof; means for biasing said vanes into abutment with the outer member, including means forming an eflective area associated with each of said vanes to exert force thereon when exposed to fluid pressure, first passage forming means in the inner member forming passages leading to each of said efiective areas, second passage forming means forming a balancing passage extending from each of said high and low pressure ports to alternately efiect communication, through said passage forming means, with the effective areas associated with said vanes, and third passage forming means forming a supplemental balancing passage, fixed relative to said outer member, extending from said working space to suc cessively connect, through said first passage forming means, the eflective area associated with each vane with said working space at a point between the high pressure port and that vane while said areas are isolated from the other balancing passages, said first, second, and third passage forming means being so proportioned and positioned that during operation said first passage forming means intermittently establish communication between said second and third passage forming means, whereby fluid pressure induced vane retraction is prevented and excessive wear is avoided.

5. A rotary fluid pressure energy translating device comprising: a stator having a central cavity therein; a rotor telcscoped into the cavity in said stator to thus form a working space; a plurality of vanes slidabe in said rotor to extend across the working space and abut the stator, said vanes, rotor, and stator cooperating to form alternately contracting and expanding working chambers; means forming high and low pressure ports in the stator adjacent said working spaces to communicate with the working chambers, in proper phase With the expansion and contraction thereof; passage forming means in the rotor communicating with the inner end of each of said vanes; cheek members, forming portions of said stator, in endwise axial abutment with said rotor; means forming vane balancing, auxiliary high and low pressure ports in said cheek members, so positioned as to register with said passage forming means; means forming a supplemental vane balancing valve port in one of said cheek members located angularly between said auxiliary high and low pressure ports and so positioned as to register with said passage forming means while said passage forming means are isolated from said auxiliary ports; and means forming a passage in said one cheek member extending from said supplemental vane balancing valve port to said working space at a point between the high pressure port and the particular vane whose passage forming means is in register with the valve port, whereby fluid pressure induced vane retraction is prevented and excessive wear is avoided.

6. A rotary fluid pressure energy translating device comprising: a stator having a central cavity therein; a rotor telescoped into the cavity in said stator to thus form a working space; a plurality of vanes slidable in said rotor to extend across the working space and abut the stator, said vanes, rotor, and stator cooperating to form alternately contracting and expanding working chambers; means forming high and low pressure ports in the stator adjacent said working spaces to communicate with the working chambers, in proper phase with the expansion and contraction thereof; passage forming means in the rotor communicating with the inner end of each of said vanes; cheek members, forming portions of said stator, in endwise axial abutment with said rotor; means forming vane balancing auxiliary high and low pressure ports in said cheek members, so positioned as to register with said passage forming means; means forming a supplemental vane balancing valve port in one of said check members located angularly between said auxiliary high and low pressure ports and so positioned as to register with said passage forming means in the rotor while said passage forming means are isolated from said auxiliary ports, said supplemental vane balancing valve port and said auxiliary high and low pressure ports being so proportioned and positioned that during operation said passage forming means in the rotor intermittently establish communication between said supplemental vane balancing valve port and said auxiliary high and low pressure ports; and means forming a passage in said one cheek member extending from said supplemental vane balancing valve port to said working space at a point between the high pressure port and the particular vane whose passage forming means is in register with the valve port, whereby fluid pressure induced vane retraction is prevented and excessive wear is avoided.

7. A rotary fluid pressure energy translating comprising: a stator having a generally elliptical central cavity therein; a rotor telescoped into the cavity in said stator to thus form a pair or generally crescent-shaped working spaces; a plurality of vanes slidable in said rotor to extend across the working spaces and abut the stator, said vanes, rotor, and stator cooperating to form alternately contracting and expanding working chambers; means in the stator adjacent said working spaces forming a pair of diametrically opposed high pressure ports and a pair of diametrically opposed low pressure ports to communicate with the working chambers, in proper phase with the expansion and contraction thereof; passage forming means in the rotor communicating with the inner end of each of said vanes; means forming four balancing passages in the stator leading to said workin spaces at points angularly between the high and low pressure ports; means forming auxiliary alternate high low pressure ports so positioned as to register with said passage for, ing means in the rotor; four supplemental vane balanciu valve port means in said stator each located angularly between said auxiliary high and low pressure ports and so positioned as to register with said passage forming means in the rotor while said passage forming means are isolated from said auxiliary ports, one communicating with each of said four balancing passages, each of said four supplemental ports and its communicating passage being so arranged as to intermittently establish communication between the inner end of each vane and a point in the working spaces between that vane and the high pressure port whereby fluid pressure induced vane retraction is prevented and excessive wear is avoided.

8. A rotary fluid pressure energy translating device comprising: a stator having a generally elliptical central cavity therein: a rotor telescoped into the cavity in device said rotor to extend across the working spaces and abut the stator, said vanes, rotor, and stator cooperating to form alternately contracting and expanding Working chambers; means in the stator adjacent said working spaces forming a pair of diametrically opposed high pres sure ports and a pair of diametrically opposed low pres sure ports to communicate with the working chambemin proper phase with the expansion and contraction thereof; passage forming means in the rotor communicating with the inner end of each of said vanes; means forming tour balancing passages in the stator leading to said working spaces at points angularly between the high and low pressure ports; means forming auxiliary :alter'nate high and low pressure ports so positioned as to register with said passage forming means in the rotor; four supplemental vane balancing valve port means in said stator each located angularly between said auxiliary high and low pressure ports and so positioned as to register with said passage forming means in the rotor while said passage forming means are isolated from said auxiliary ports, one communicating with each of said four balancing passages, each of said four supplemental ports and its communicating passage being so arranged as to intermittently establish communication between the inner end of each vane and a point in the working spaces between that vane and the high pressure port whereby fluid pressure induced vane retraction is prevented and excessive wear is avoided, said supplemental valve ports and said auxiliary ports being so proportioned and positioned that during operation said passage forming means in the rotor intermittently establish communication therebetween 9. In a fluid pressure energy translating device of the type having a stator, a rotor, a plurality of vanes slideably extending from the rotor to abut the stator and thus form a plurality of expansible working chambers bounded by adjacent vanes and distributed around the rotor, a port in the rotor communicating withwthe underside of each vane, valve means in said stator inclu'ding high and low pressure ports alternately connectable with said working chambers and angularly spaced apart by transition Zones of sufficient extent to interrupt communication bea tween the chambers, and ports and thus provide closed center valving, and high and low pressure balancing ports in said stator to alternately communicate with said ports in the rotor, that improvement comprising: a supplemental balancing port in said stator spaced between said high and low pressure balancing ports to communicate with each of said vports in the rotor while a working chamber bounded by the vane associated with that port is, in the isolation of said transition zone; and fluid passage means in said stator to connect said supplemental port to said transition zone, whereby pressure in said transition zone is conducted to the underside of said vanes.

References Cited in thetfile of this patent UNITED STATES PATENTS 317,751 Dunfee May 12, 1885 1,093,005 Myers Apr. 14, 1914 1,539,728 Ensign May 26, 1925 1,854,692 Cooper Apr. 19, 1932 2,256,459 Kendrick Sept. 16, 1941 2,387,761 Kendrick Oct. 36, 1945 2,455,297, Curtis et a1 Nov. 30, 1948 2,544,988 Gardiner et a1 Mar. 13, 1951 2,622,538 Vincent Dec. 23, 1952 2,739,539 Gardiner Mar. 27, 1956 

